Rotor disk

ABSTRACT

An impeller ( 1 ), in particular a radial-flow fan or compressor impeller is proposed for an internal combustion engine. This impeller has an unequal number of full blades and split blades ( 4, 5 ) arranged at a different angular distance and in a different order. This further reduces the noise produced.

[0001] This application is the U.S. National Stage application ofPCT/EP02/04920, filed May 4, 2002, which claims the priority of GermanPatent Application No. 101 22 516.4, filed May 9, 2001, the disclosuresof which are expressly incorporated by reference herein.

[0002] The present invention relates generally to an impeller, inparticular a radial-flow fan or a compressor impeller having a differentnumber of full blades and split blades.

[0003] In internal combustion engines, impellers are used, e.g., asradial-flow fans or as compressor impellers for an exhaust gasturbocharger. One problem with these impellers is the generated noise,which is often perceived as unpleasant. One measure commonly used fornoise reduction consists of equipping the impeller with full blades andsplit blades. Such an embodiment is known from European Patent 0 439 267B1. In addition, the number of full blades on this impeller may bedifferent from the number of split blades.

SUMMARY OF THE INVENTION

[0004] An object of the present invention is to further reduce the noiseemission by an impeller.

[0005] This object is has been achieved by arranging the full blades andthe split blades at a different angular distance and in a differentorder.

[0006] The present invention thereby greatly reduces the noise level.Due to these measures, the acoustic power is distributed among severalindividual tones, the intensity of which turns out to be accordinglylower. Another advantage is that the efficiency and power consumption ofthe impeller remain almost constant. Due to the use of an alternativematerial, e.g., aluminum, the mass moment of inertia of the impeller isreduced. In actual practice, this means that a much better responsecharacteristic is achieved in an impeller having a diameter of, forexample, 670 mm.

[0007] Through appropriate shaping of the rear side of the impeller, acoupling and a bearing can be integrated. This yields the advantage thatthe component density is increased while the overall height remains thesame. As a consequence, this results in a configuration that is easierto install.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These and other objects, features and advantages of the presentinvention will become more readily apparent from the following detaileddescription of currently preferred configurations thereof when taken inconjunction with the accompanying drawings wherein:

[0009]FIG. 1 is a perspective view of an impeller in accordance with thepresent invention;

[0010]FIG. 2 is a sectional top view of the impeller of FIG. 1;

[0011]FIG. 3 is a sectional side view of the impeller of FIG. 1; and

[0012]FIG. 4 is a side sectional view of an impeller having anintegrated coupling.

DETAILED DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 shows an impeller 1, in particular a radial-flow fan orcompressor impeller. It consists of a cover plate 2, a base plate 3, ahub 6 with a mounting hole 7 and blades. The blades of the impeller 1are configured as full blades 4 and split blades 5. The geometry of thefull blades is not identical to that of the split blades here becausethe split blades form part of the full blades. The full blades 4 andsplit blades 5 are arranged at a different angular distance and in adifferent order, the arrangement and order of which can be seen from thesectional diagram in FIG. 2. For example, the split blade 5.1 isfollowed by a full blade 4.1, then a split blade 5.2, followed by fourfull blades 4.2 to 4.5 and a split blade 5.3. The noise generated isfurther reduced due to the different angular distance and the differentorder while achieving almost the same efficiency and/or powerconsumption. The level and frequency of the noise, which is perceived asunpleasant, are reduced by these measures and distributed over a broaderfrequency band. Due to these structural measures, the acoustic power isdistributed among several individual tones, the intensity of which turnsout to be accordingly lower.

[0014] The impeller 1 is preferably made of an alternative material,e.g., aluminum. This results in a significant reduction in the massmoment of inertia. The impeller 1 shown in FIG. 1 also has balancingholes 8. An imbalance in the impeller 1 is compensated by thesebalancing holes 8. This reduces manufacturing costs because it is nolonger necessary to mount additional balancing weights.

[0015]FIG. 2 shows a first area 15 and a second area 16. Only fullblades 4 are arranged in the first area 15. Both full blades and splitblades are arranged in the second area 16. The order of the full blades4.1 through 4.6 and the split blades 5.1 through 5.4 is irregular in thesecond area 16. The angles between two blades on the air intake side andthe air outlet side are identical. The angle x1 between the split blade5.1 and the full blade 4.1 thus corresponds to the angle x2. The angley1 between the full blade 4.1 and the split blade 5.2 corresponds to theangle y2. The same is also true of the angles z1 and z2. However, theseangles are different from one another, i.e., x1 is not equal to y1 andis not equal to z1. On the whole, the order of the full blades 4 and thesplit blades 5 is not rotationally symmetrical, not even in segments.

[0016]FIG. 3 shows the impeller 1 in a side view. The direction of flowof the air is indicated with arrows. As shown here, the air is conveyedby the impeller 1 in the axial direction, i.e., radially outward, fromabove in the direction of the drawing. In addition, FIG. 3 shows thearrangement of the full blades and the split blades between the coverplate 2 and the base plate 3.

[0017]FIG. 4 shows the impeller 1 with an integrated coupling and acoupling housing 9. The coupling housing 9 is integrated into theimpeller 1 on the rear side 13. This arrangement provides the advantagethat a greater component density is achieved with the same overallheight of the impeller. Reference numeral 10 denotes the connection fora housing, e.g., a gear box. The impeller 1 is detachably connected to awheel mount 11 by a screw 14 from the front side 12. The wheel mount 11is in turn fixedly connected to the coupling and the coupling housing 9.The impeller 1 is activated or deactivated on the basis of the status ofthe coupling 9.

[0018] Although the present invention has been illustrated and describedwith respect to exemplary embodiment thereof, it should be understood bythose skilled in the art that the foregoing and various other changes,omission and additions may be made therein and thereto, withoutdeparting from the spirit and scope of the present invention. Therefore,the present invention should not be understood as limited to thespecific embodiment set out above but to include all possibleembodiments which can be embodied within a scope encompassed andequivalent thereof with respect to the feature set out in the appendedclaims.

1. Impeller for a radial-flow fan or compressor impeller, comprisingfull blades and split blades different in number from the full blade,wherein the full blades and the split blades are arranged at a differentangular distance and in a different order.
 2. Impeller as claimed inclaim 1, further comprising a coupling and a bearing integrated on arear side of the impeller.
 3. Impeller as claimed in claim 2, whereinthe impeller is made of a material selected to minimize mass moment ofinertia.
 4. Impeller as claimed in claim 3, wherein balancing holes arearranged on the impeller to compensate for an imbalance in the fanwheel.
 5. Impeller as claimed in claim 4, wherein the balancing holesare arranged on at least one of a cover plate and a base plate. 6.Impeller as claimed in claim 1, wherein the impeller is made of amaterial selected to minimize mass moment of inertia.
 7. Impeller asclaimed in claim 1, wherein balancing holes are arranged on the impellerto compensate for an imbalance in the fan wheel.
 8. Impeller as claimedin claim 7, wherein the balancing holes are arranged on at least one ofa cover plate and a base plate.